Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Air Force Institute of Technology

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 3781 - 3810 of 5600

Full-Text Articles in Entire DC Network

Cross Range Smear Characterization In Xpatch Isar Images, Peter E. Muend Mar 2004

Cross Range Smear Characterization In Xpatch Isar Images, Peter E. Muend

Theses and Dissertations

This thesis investigates a cross range smear phenomenon seen in far field, frequency domain Xpatch calculations. The phenomenon is very subtle, manifesting itself in 2-D ISAR images as a low-level scatterer response smeared in the cross range direction. This cross range smear occurs only using complex target models with certain characteristics. It is also a mathematical construct, not occurring in physical SAR systems. Using a carefully constructed scattering target set, Xpatch-generated ISAR images are used to characterize cross range smear in terms of its input parameters. The characterization is done as a DOE-based polynomial approximation to the observed smear levels. …

Go to article

Surveying Cost Growth, Michael A. Greiner, Vince Sipple, Edward D. White Jan 2004

Surveying Cost Growth, Michael A. Greiner, Vince Sipple, Edward D. White

Faculty Publications

Cost growth that weapon systems incur throughout their acquisition life cycle concerns those who work in the acquisition environment. One way to reduce the amount of unexpected cost growth is to develop better cost estimates. In attaining better cost estimates though, it is often helpful to understand and account for potential cost drivers. Several cost studies, some of which specifically focus on the aircraft industry, have been performed documenting and investigating these growth factors. Overviews of these various cost growth studies are presented as other tools for the cost estimators and program managers.

Go to article

Generalized Residual Multiple Model Adaptive Estimation Of Parameters And States, Charles D. Ormsby Oct 2003

Generalized Residual Multiple Model Adaptive Estimation Of Parameters And States, Charles D. Ormsby

Theses and Dissertations

This dissertation develops a modification to the standard Multiple Model Adaptive Estimator (MMAE) which allows the use of a new "generalized residual" in the hypothesis conditional probability calculation. The generalized residual is a linear combination of traditional Kalman filter residuals and "post-fit" Kalman filter residuals which are calculated after measurement incorporation. This modified MMAE is termed a Generalized Residual Multiple Model Adaptive Estimator (GRMMAE). The dissertation provides a derivation of the hypothesis conditional probability formula which the GRMMAE uses to calculate probabilities that each elemental filter in the GRMMAE contains the correct parameter value. Through appropriate choice of a single …

Go to article

Cooperative Control Simulation Validation Using Applied Probability Theory, Christopher S. Schulz Sep 2003

Cooperative Control Simulation Validation Using Applied Probability Theory, Christopher S. Schulz

Theses and Dissertations

Several research simulations have been created to support development and refinement of teamed autonomous agents using decentralized cooperative control algorithms. Simulation is the necessary tool to evaluate the performance of decentralized cooperative control algorithms, however these simulations lack a method to validate their output. This research presents a method to validate the performance of a decentralized cooperative control simulation environment for an autonomous Wide Area Search Munition (WASM). Rigorous analytical methods for six wide area search and engagement scenarios involving Uniform, Normal, and Poisson distributions of N real targets and M false target objects are formulated to generate expected numbers …

Go to article

A Communications Modeling System For Swarm-Based Sensors, Brian A. Kadrovach Sep 2003

A Communications Modeling System For Swarm-Based Sensors, Brian A. Kadrovach

Theses and Dissertations

Today's information age has exploded the amount of data available to decision makers at all levels of the control hierarchy. The miniaturization and proliferation of sensor technology has enabled extensive detection and monitoring and advances in computational capabilities have provided for embedded data analysis and the generation of information from raw data. Additionally, with the miniaturization of mechanical systems it is possible to provide platforms for sensor suites that are capable of mobility and limited autonomy. Swarming or bio-emergent behavior problems, provides a robust scalable mechanism for organizing large numbers of mobile sensor platforms. However, the mobility dynamics of swarm …

Go to article

Broadening And Shifting Of Atomic Strontium And Diatomic Bismuth Spectral Lines, Jeremy C. Holtgrave May 2003

Broadening And Shifting Of Atomic Strontium And Diatomic Bismuth Spectral Lines, Jeremy C. Holtgrave

Theses and Dissertations

The objective of this research is to study the effects of noble gases on atomic strontium and diatomic bismuth visible transitions, Specifically, this research seeks to determine if the line broadening and, in the case of atomic strontium, line shifting rates of these transitions in the presence of noble gases depend on the total angular momenta of the energy states involved. It has been known for more than a century that atomic and molecular spectral lines are broadened and shifted by perturbing species. While a considerable body of theoretical work has been accomplished on this topic over the years, only …

Go to article

Transient Analysis And Applications Of Markov Reward Processes, Jeffrey A. Sipe Mar 2003

Transient Analysis And Applications Of Markov Reward Processes, Jeffrey A. Sipe

Theses and Dissertations

In this thesis, the problem of computing the cumulative distribution function (cdf) of the random time required for a system to first reach a specified reward threshold when the rate at which the reward accrues is controlled by a continuous time stochastic process is considered. This random time is a type of first passage time for the cumulative reward process. The major contribution of this work is a simplified, analytical expression for the Laplace-Stieltjes Transform of the cdf in one dimension rather than two. The result is obtained using two techniques: i) by converting an existing partial differential equation to …

Go to article

Spacecraft Charging At Geosynchronous Altitudes: Current Balance And Critical Temperature In A Non-Maxwellian Plasma, Jose T. Harris Mar 2003

Spacecraft Charging At Geosynchronous Altitudes: Current Balance And Critical Temperature In A Non-Maxwellian Plasma, Jose T. Harris

Theses and Dissertations

Spacecraft charging threatens to disable spacecraft components and adversely impact any satellite function. Electrostatic charge, and especially discharge, can hinder the proper operation of, or destroy, spacecraft components, thereby rendering the spacecraft ineffective or inoperative. The level of charging is dependent on the particle energy (speed) distribution. Current spacecraft design and material provide limited protection against the dangers of electrostatic discharge, and active measures such as beam emission are also employed.

Go to article

Characterization Of Chlorinated Solvent Degradation In A Constructed Wetland, Nathan D. Clemmer Mar 2003

Characterization Of Chlorinated Solvent Degradation In A Constructed Wetland, Nathan D. Clemmer

Theses and Dissertations

Widespread chlorinated ethene contamination of aquifers coupled with high costs of current treatment technologies demand innovative remediation solutions. Wetlands, maintaining anaerobic and aerobic zones promoting the complete degradation of chlorinated ethenes such as Tetrachloroethylene (PCE), could be the answer. This thesis characterized the chlorinated solvent contamination levels in three strata of an upward flow constructed wetland. Analysis of samples was accomplished by purge-and-trap gas chromatography. Water quality parameters, Dissolved Oxygen (DO), Oxidation Reduction Potential (ORP), pH, Conductivity, and Temperature, were also measured in monitoring wells with a water monitoring sonde. After removing data outliers caused by short-circuiting flow, PCE concentrations …

Go to article

An Analysis Of The Efficacy Of The Logistics Composite Model In Estimating Maintenance Manpower Productive Capacity, Kirk B. Pettingill Mar 2003

An Analysis Of The Efficacy Of The Logistics Composite Model In Estimating Maintenance Manpower Productive Capacity, Kirk B. Pettingill

Theses and Dissertations

The Logistics Composite Model (LCOM) is the tool of choice for many MAJCOM's (ACC, USAFE, AFMC) in determining maintenance manpower requirements. The LCOM is a simulation program capable of modeling the manpower, equipment, supplies, and facilities required to conduct aircraft maintenance activities, Manpower studies conducted with the LCOM result in manpower estimates that end up in Unit Manning Documents (UMD) as "LCOM earned," authorized positions. This research effort focuses on whether the LCOM can also be used to determine maintenance manpower's current capacity. Three different flying units at Cannon AFB, NM were modeled to determine if the LCOM, when programmed …

Go to article

Comparison Of The Refractive Index Structure Constant Derived From Numerical Weather Prediction (Nwp) Models And Thermosonde Data, De Leon C. Narcisse Mar 2003

Comparison Of The Refractive Index Structure Constant Derived From Numerical Weather Prediction (Nwp) Models And Thermosonde Data, De Leon C. Narcisse

Theses and Dissertations

An accurate depiction of atmospheric turbulence is required for successful employment of a viable airborne laser for the Department of Defense (DOD). The ABL Special Program Office (SEC) which is tasked by the Missile Defense Agency (MDA) bas not designated any particular numerical weather model that is tasked exclusively to model optical turbulence This research compares CLEAR1, 2 X CLEAR I and thermosonde derived values of the refractive index structure constant to optical turbulence values derived from several numerical weather prediction models currently in use by the DOD. The models used were the fifth Generation Mesoscale Model (MM5), the Coupled …

Go to article

Evaluating The Performance Of Multiple Classifier Systems: A Matrix Algebra Representation Of Boolean Fusion Rules, Justin M. Hill Mar 2003

Evaluating The Performance Of Multiple Classifier Systems: A Matrix Algebra Representation Of Boolean Fusion Rules, Justin M. Hill

Theses and Dissertations

Given a finite collection of classifiers one might wish to combine, or fuse, the classifiers in hopes that the multiple classifier system (MCS) will perform better than the individuals. One method of fusing classifiers is to combine their final decision using Boolean rules (e.g., a logical OR, AND, or a majority vote of the classifiers in the system). An established method for evaluating a classifier is measuring some aspect of its Receiver Operating Characteristic (ROC) curve, which graphs the trade-off between the conditional probabilities of detection and false alarm. This work presents a unique method of estimating the performance of …

Go to article

Calculation Of The Actual Cost Of Engine Maintenance, Oguz Ezik Mar 2003

Calculation Of The Actual Cost Of Engine Maintenance, Oguz Ezik

Theses and Dissertations

The cost of military operations has been difficult to determine, yet considered of high importance. The cost of an operation is largely dependent upon the answers to subordinate questions involving the discrete costs of military activities, like supporting individual items, While different cost estimates have received attention from the media, the question arises as to how accurate these figures are, There have been numerous studies performed by the Operations Research analysts to minimize costs while allocating scarce resources, However, the values of these studies are dependent upon whether or not the cost figures used are sufficiently "true" or accurate, This …

Go to article

Optimum Component Design In N-Stange Series Systems To Maximize The Reliability Under Budget Constraint, Huseyin Gozebe Mar 2003

Optimum Component Design In N-Stange Series Systems To Maximize The Reliability Under Budget Constraint, Huseyin Gozebe

Theses and Dissertations

This research is intended to find a new heuristic for solving the reliability optimization of n-stage series system. The new heuristic will make the initial system design and use redundancy to improve system reliability level. The limited capacity of common optimization tools requires the new heuristic to be coded in VBA programming language. Moreover, the known reliability optimization heuristic, marginal analysis will be coded so that the difference between two heuristics can be seen and design engineers can use the best result in their applications.

Go to article

The Air Warrior's Value Of National Security Space, John D. Loftis Mar 2003

The Air Warrior's Value Of National Security Space, John D. Loftis

Theses and Dissertations

The 2001 Report of the Commission to Assess United States National Security Space Management and Organization recommended that U.S. efforts in national security space be elevated to the highest national security priority. With more focused high-level attention on national security space decisions a measure that captures and quantities the value of space capabilities to combat operations professionals is desired. This thesis models what the air warriors desire from space assets in combat. A Value-Focused Thinking (VFT) approach was used to elicit values from air combat experts with operational experience. An initial Gold Standard value model was constructed and validated by …

Go to article

A Service Life Analysis Of Coast Guard C-130 Aircraft, Jonathan B. Duff Mar 2003

A Service Life Analysis Of Coast Guard C-130 Aircraft, Jonathan B. Duff

Theses and Dissertations

The U. S. Coast Guard, much like the rest of the Armed Services, is facing a dramatic transformation of its forces to meet current and future service requirements. The Coast Guard has responded to this transformation by initiating the Deepwater System, a complete review of the offshore mission requirements and the modernization of its infrastructure. In particular, Deepwater will review and modernize the Coast Guard's aviation assets, improving aircraft systems, airborne sensors, and communications and information management systems. However, these capability advancements will take time and money to implement, and will require careful management of the current resources to ensure …

Go to article

Deterministic Intracellular Modeling, Jacqueline B. Young Mar 2003

Deterministic Intracellular Modeling, Jacqueline B. Young

Theses and Dissertations

The United States Air Force is interested in the potential side effects at the cellular level from exposure to mission-essential chemicals. Presently, Air Force toxicology studies are conducted to help shed light in identifying potential hazards to workers. However, it takes a considerable amount of money, resources, and time to obtain and analyze experimental results from toxicology studies. The necessity for innovative methods that enable researchers to more effectively generate and analyze data is apparent.

Go to article

Implementing An Information Retrieval And Visualization Framework For Heterogeneous Data Types, Andrew J. Kowalchuk Mar 2003

Implementing An Information Retrieval And Visualization Framework For Heterogeneous Data Types, Andrew J. Kowalchuk

Theses and Dissertations

In today's information focused world, there is no lack of entities focused on information gathering. However, there is still a widespread epidemic of information starvation in the Department of Defense (DoD). This starvation is attributed to the lack of interoperability between information gatherers and information consumers. To alleviate this problem, the DoD has put forth a vision of a Joint Battlespace Infosphere (JBI). This research proposes a framework for sharing and finding resources in a JBI. The framework uses an extensible metadata specification, agent technology, and the Control of Agent Based Systems (CoABS). It provides several tools for publication and …

Go to article

Analyze The Air Force Methods For Facility Sustainment And Restoration, Ronald C. Cole Mar 2003

Analyze The Air Force Methods For Facility Sustainment And Restoration, Ronald C. Cole

Theses and Dissertations

The Department of Defense (DoD) is improving the procedures for identifying, advocating, allocating funding, and accomplishing facility requirements to improve the readiness capability to support the mission. The purposes of this research were to fully explore the methodologies employed by the Air Force (AF) and try to capitalize on industry standard practices to improve the AF methods. Industry has conducted extensive research devoted to the development of predictive models to estimate facility maintenance or sustainment requirements. The DoD and the AF have already implemented the facility sustainment model (FSM) to predict facility sustainment requirements; now however, they are struggling with …

Go to article

The Effects Of Gps M-Code On Radar Detection, Jae K. Yang Mar 2003

The Effects Of Gps M-Code On Radar Detection, Jae K. Yang

Theses and Dissertations

The GPS system is undergoing a modernization effort which will add several new signals to be placed at the L1, L2, and L5 frequency bands. One of the signals to be placed on L2 is a new military code (M-code) which may be transmitted at a higher power level than current GPS signals. Other users of the L2 frequency band are concerned with the potential interference that may be caused by the increase in power of the GPS signal. One particular use of the 1215-1400 MHz frequency band is Air Traffic Control (ATC) radar applications.

Go to article

Antecedents And Outcomes Of End User Computing Competence, David A. Case Mar 2003

Antecedents And Outcomes Of End User Computing Competence, David A. Case

Theses and Dissertations

The tremendous proliferation of end user computing (EUC) in the workplace over the past few decades is cause for concern in public and private organizations. Computer use has moved from individuals working with "dumb" terminals in centralized networks to individuals operating personal computers, just as powerful as yesterday's mainframe. The end user has had to evolve and will continue evolving as well; from someone with low level technical skills to someone with a high level of technical knowledge and information managerial skills. Because EUC continues growing more sophisticated, end users must not only maintain a level of competence, but prepare …

Go to article

Characterizing Data Streams Over Ieee 802.11b Ad-Hoc Wireless Networks, John T. Wagnon Mar 2003

Characterizing Data Streams Over Ieee 802.11b Ad-Hoc Wireless Networks, John T. Wagnon

Theses and Dissertations

Soon, advancements in data encryption technology will make real-time decryption of the contents of network packets virtually impossible. This research anticipates this development and extracts useful information based on packet level characteristics. Distinguishing characteristics from e-mail, HTTP, print, and FTP applications are identified and analyzed. The analysis of collected data from an ad-hoc wireless network reveals that distinguishing characteristics of network traffic do indeed exist. These characteristics include packet size, packet frequency, inter-packet correlation, and channel utilization. Without knowing the contents of packets or the direction of the traffic flow, the applications accessing the wireless network can be determined.

Go to article

Effect Of Multi-Mode Vibration On Signature Estimation Using A Laser Vibration Sensor, Ngoya Pepela Mar 2003

Effect Of Multi-Mode Vibration On Signature Estimation Using A Laser Vibration Sensor, Ngoya Pepela

Theses and Dissertations

A laser vibration sensor (LVS) can be used to determine the vibrational spectrum of targets such as vehicles using heterodyne laser Doppler velocimetry. The vibrational spectra of exterior skin of vehicles are known to have characteristic resonances due to the physical structure driven by motor gears and other moving parts. Each particular class of vehicle has a unique vibrational spectrum. This research shows how a body vibrating in higher order modes has the opportunity to eliminate spectral content of the target's vibrational spectrum while using an LVS to perform spectrum estimation. This is due to roughly equal amounts of laser …

Go to article

Forecasting Excessive Rainfall And Low-Cloud Bases East Of The Northern Andes And Mesoscale Convective Complex Movement In Central South America, Marc R. Gasbarro Mar 2003

Forecasting Excessive Rainfall And Low-Cloud Bases East Of The Northern Andes And Mesoscale Convective Complex Movement In Central South America, Marc R. Gasbarro

Theses and Dissertations

This research produces better forecast tools for SOUTHCOM's 25th Operational Weather Squadron (OWS) over multiple areas of operation in South America. Heavy rainfall and low-cloud base events along the northeastern Andes foothills are examined, as well as, mesoscale convective complexes (MCCs) in Central South America (CSA). Low clouds, fog, and flooding rains hamper daily Department of Defense (DoD) counter-drug operations in Northwestern South America (NWSA). In addition, fierce MCCs interfere with joint-military exercises in CSA.

Go to article

A Decision Support System For Effective Scheduling In An F-16 Pilot Training Squadron, Davut Aslan Mar 2003

A Decision Support System For Effective Scheduling In An F-16 Pilot Training Squadron, Davut Aslan

Theses and Dissertations

Scheduling of flights for a flight training squadron involves the coordination of time and resources in a dynamic environment. The generation of a daily flight schedule (DFS) requires the proper coordination of resources within established time windows. This research provides a decision support tool to assist in the generation of the DFS. Three different priority rules are investigated for determining an initial ordering of flights and a shifting bottleneck heuristic is used to establish a candidate DFS. A user interface allows a scheduler to interact with the decision support tool during the DFS generation process. Furthermore, the decision support tool …

Go to article

Statistical Process Control: An Application In Aircraft Maintenance Management, Bradley A. Beabout Mar 2003

Statistical Process Control: An Application In Aircraft Maintenance Management, Bradley A. Beabout

Theses and Dissertations

Maintenance management at the 135th Airlift Wing, Maryland Air National Guard desires a visualization tool for their maintenance performance metrics. Currently they monitor their metrics via an electronic spreadsheet. They desire a tool that presents the performance information in a graphical manner. This thesis effort focuses on the development of a visualization tool utilizing two of the seven tools offered by Statistical Process Control (SPC). This research demonstrates the application of p-charts and Pareto diagrams in the aircraft maintenance arena. P-charts are used for displaying mission capable (MC) rates and flying scheduling effectiveness (FSE) rates. Pareto diagrams are then used …

Go to article

Stress Analysis Of Silicon Carbide Microeletromechanical Systems Using Raman Spectroscopy, Stanley J. Ness Mar 2003

Stress Analysis Of Silicon Carbide Microeletromechanical Systems Using Raman Spectroscopy, Stanley J. Ness

Theses and Dissertations

During the fabrication of Micro-Electro-Mechanical Systems (MEMS), residual stress is often induced in the thin films that are deposited to create these systems. These stresses can cause the device to fail due to buckling, curling, or fracture. Government and industry are looking for ways to characterize the stress during the deposition of thin films in order to reduce or eliminate device failure. Micro-Raman spectroscopy has been successfully used to analyze poly-silicon MEMS devices made with the Multi-User MEMS Process (MUMPS trade name). Micro-Raman spectroscopy was selected because it is nondestructive, fast and has the potential for in situ stress monitoring. …

Go to article

Search Theory And U-Boats In The Bay Of Biscay, Ronald Gregory Carl Mar 2003

Search Theory And U-Boats In The Bay Of Biscay, Ronald Gregory Carl

Theses and Dissertations

Threats to our nation's resources and forces are becoming increasingly lethal and mobile. Therefore, our ability to locate and interdict these threats is more important than ever. Search theory is one tool that is vital to countering the increasing threat. This research presents a multi-agent simulation, built around the Allied search for U-boats in the Bay of Biscay during World War II, which extends several classic search theory algorithms. Comparison of techniques is based on the effectiveness of finding high- valued, mobile assets. A JAVA-based multi-agent simulation model is designed, built and tested, and used to demonstrate the existence of …

Go to article

Analysis Of Organizational Architectures For The Air Force Tuition Assistance Program, Krista Z. Lapietra Mar 2003

Analysis Of Organizational Architectures For The Air Force Tuition Assistance Program, Krista Z. Lapietra

Theses and Dissertations

The consideration of restructuring through a change in organizational architecture is often a fiercely debated issue within an organization. The argument for restructuring to improve quality, customer service, and financial management is pitted against perceived lack of job security and historically poor results from previous restructuring initiatives. To balance all sides when considering a change in organizational architecture, the organization should use a method of evaluating potential architectures that assists in determining the best new architecture and generates support from those involved. The objective of this research is to provide the Air Force Education Division with a defendable methodology for …

Go to article

An Analysis Of Multiple Layered Networks, Kevin T. Kennedy Mar 2003

An Analysis Of Multiple Layered Networks, Kevin T. Kennedy

Theses and Dissertations

Current infrastructure network models of single functionality do not typically account for the interdependent nature of infrastructure networks. Infrastructure networks are generally modeled individually, as an isolated network or with minimal recognition of interactions. This research develops a methodology to model the individual infrastructure network types while explicitly modeling their interconnected effects. The result is a formulation built with two sets of variables (the original set to model infrastructure characteristics and an additional set representing cuts of interdependent elements). This formulation is decomposed by variable type using Benders Partitioning and solved to optimality using a Benders Partitioning algorithm. Current infrastructure …

Go to article

First Prev Next Last